Coffee chemistry: is Generation Y addicted?

It’s the socially acceptable drug we can cheerfully drink any time of the day or night but is caffeine doing us more harm than good? Emma Lloyd investigates the consequences for Generation Y addicts.

It’s a familiar aroma that seems to speak directly to your soul as it wafts gently from passing cafes. The scent promises a delicious, piping hot cup of Alert!, deliverable into your grateful hands for less than $5. Your brain is kicked into gear and firing on all cylinders within the hour.

Coffee. It’s a wonderful thing.

It’s a drink that Australians are becoming increasingly familiar with. Dropping into a cafe for a quick fix is on the rise, while visiting the local pub is becoming less popular as time goes on. However, according to a 2012 survey, we’re also becoming increasingly familiar with the withdrawal effects of caffeine addiction. Generation Y in particular is feeling the pain: 42 per cent of younger coffee drinkers reported withdrawal headaches from lack of caffeine, and 35 per cent have shelled out over $1000 for an espresso machine. On average, each of us drink about four cups per day.

But how, exactly, does caffeine give us such a kick-start in the mornings? I invite you to grab a cup of glorious, smooth coffee and follow the beverage through your system. Come on. It’ll be an adventure.

A MIRACULOUS MOLECULE

About 20 minutes after your first sip, the caffeine molecules from your drink cross through the wall of the stomach or intestines and are absorbed straight into your bloodstream, where it spreads throughout your body. It also makes its way up to your brain where it crosses the blood-brain barrier. This protective barrier is designed to prevent large particles, such as bacteria or some toxins, from reaching (and potentially damaging) your brain but caffeine breezes through without a problem.

You’re starting to perk up a little as your feeling of alertness increases. The caffeine is busy being obstructive by binding to adenosine receptors. Adenosine is a hormone found throughout the body and its main function in the brain is to promote sleep and relaxation. In your case, caffeine molecules are stopping adenosine from reaching the receptors, and therefore stopping you from feeling sleepy.

Caffeine also prompts the release of adrenaline, which raises your heart rate, tightens your muscles and dilates your pupils. Finally, caffeine increases levels of dopamine, a neurotransmitter that plays a role in general cognition, attention, movement and mood.

Time passes. Your energy levels start to slump and you feel the need to go to the bathroom. Your liver has metabolised the caffeine and broken it down into three new molecules: paraxanthine, theobromine (which is also found in chocolate) and theophylline. These compounds, along with caffeine, are classed as methylated xanthines, and they have a number of effects around the body. Like caffeine, they raise your heart rate, increase your alertness, reduce inflammation, stimulate respiration and increase urine production – so your dash to the bathroom is unsurprising.

A day or two goes by and you have been avoiding the coffee cart. You’re starting to regret it: the pounding headache, inability to stay awake and lack of concentration are ruining your day. Thanks to being a habitual caffeine drinker, your body has built up a tolerance to the substance.

Since caffeine normally decreases blood flow in the brain, you are now experiencing increased blood flow due to the lack of it, producing that pounding headache. Electrical activity in the brain has also changed, with increased theta waves causing that sluggish sensation you’re feeling.

It’s time, you think, for another visit to that cheerful barista with the cute accent – and for the cycle to start all over again.

It seems caffeine is studied almost as widely as it is consumed, leaving the Internet awash with advice and information. The Australian Dieticians Association recommends drinking coffee in moderation – no more than five cups per day – and even says that caffeine contains antioxidants that promote good health. Curiously, some research suggests that coffee drinkers live slightly longer than those who don’t indulge. Whether this is because of their penchant for cappuccinos or not is still unknown.

But some of coffee’s most interesting effects occur purely at the psychological level. Simply cradling a hot cuppa in our hands makes us more likely to judge other people as having “warm” personalities, and ingesting caffeine renders us more open to persuasion. Coffee and stress, however, aren’t a great mix – caffeine can have hallucinatory effects if you drink enough.

Unfortunately it’s not all good news. National University of Ireland’s Professor Jack E. James (who quite literally wrote the book on caffeine) cautions against coffee consumption, saying “claims that dietary caffeine is of little importance to health are ill founded”. Thanks to its blood-pressure-raising properties, caffeine contributes to cardiovascular disease (although other research tentatively suggests that coffee also contributes to better cardiovascular health because it has anti-inflammatory properties – go figure.) It’s also risky for pregnant mothers since caffeine easily crosses the placenta.

TOTALLY ADDICTED?

So is Generation Y really addicted to coffee? And if so, what are the consequences?

Professor Ian Marshall, director of the University of Sydney Health Service, thinks there are bigger fish to fry than caffeine addiction for Generation Y. “In my experience, many students don’t get enough sleep and become sleep deprived,” he says. “This is not due to caffeine use but more often to lifestyle. I occasionally see students with acute caffeine intoxication but I can’t remember seeing anyone with caffeine withdrawal.”

And if caffeine isn’t the best thing to help you stay awake, what is?

“Get more sleep! There is no better solution,” he says.

It’s sound, professional medical advice that we all know we should follow – and yet Generation Y’s love affair with caffeine looks sure to continue regardless. It’s a brew too good to be true.

In the mood for more? For an entertaining look at how coffee gets from the tree to our bodies, check out CGP Grey’s videohere.